Field of the Invention
The present invention relates to a communication apparatus configured to perform communication via a communication path, a communication method, a communication system, and a storage medium.
Description of the Related Art
It is common for a client device (hereinafter, “client”) to connect to a remote server via a network to upload images. At this time, an application of the client is connected to the remote server using the Hypertext Transfer Protocol (HTTP). At the time of the connecting to the remote server, if a buffer size is not set as appropriate, there arises an issue that a communication band cannot be used effectively. To overcome the problem, a method has been discussed in which a congestion window size is adjusted based on the measurement of a round trip time (RTT) and the cause of a packet loss (Japanese Patent Application Laid-Open No. 2014-90367).
The Internet Engineering Task Force (IETF) has submitted HTTP version 2 (HTTP/2), which is the successor of HTTP/1.1. In HTTP/2, a window size corresponding to a buffer for performing data transmission/reception is set with respect to both a connection and a stream. In HTTP/2 communication based on an initial window size, a communication band may not be used effectively.
For example, in a case where the technique discussed in Japanese Patent Application Laid-Open No. 2014-90367 is applied to HTTP/2, a Transmission Control Protocol (TCP) congestion window size can be adjusted. However, the HTTP/2 connection and stream window sizes are not set, so that effective use of a band in the communication is not possible. This may cause a delay in uploading of images from a client to a server and in downloading images from the server to the client.
For example, in an environment with a delay (RTT) of 30 ms with respect to a window size of 16 kilobytes, the maximum bandwidth is 16 Mbps. Thus, the bandwidth-use efficiency may decrease under high-speed lines such as common wireless lines of IEEE 802.11n and IEEE 802.11ac standards, cable television lines, optical lines, etc.